1. Field of the Invention
The present invention generally relates to testing electronic circuits and power systems and more specifically relates to electronic load systems for testing electronic circuits and power systems.
2. Description of the Related Art
An electronic load system simulates loading on an electronic circuit. Electronic Loads are suitable for testing and characterizing a wide range of power sources, such as power supplies, batteries, generators, fuel cells, solar cells and other power components. Unlike passive resistive loads, which have a single pre-determined load current, electronic loads may operate under multiple modes such as constant current (CC), constant voltage (CV), constant power (CW) and constant resistance (CR), and offer a wide variety of voltage and current ranges. When using an electronic load, the load current may be varied within a defined range, and may be regulated electronically. Electronic loads may be used to simulate dynamic behaviors using a built-in transient generator and versatile triggering options to allow the dynamic load behavior to be synchronized with other events.
The equipment and power spectrum of electronic loads begins with simple circuits including a potentiometer for current setting and a transistor circuit for power transforming. During operation, the electronic load consumes electric energy and transforms it into heat energy. Fans or water-cooled elements may be used for cooling the system. Settings and measured values such as input voltage and actual load current are typically shown on a visual display. Electronic load systems may be controlled by a PLC or remotely by a PC.
A dynamic electronic load module typically uses a plurality of relatively expensive field effect transistor (FET) circuits that enables the module to operate under a wide variety of voltage and current ranges. Passive resistive loads are less expensive than FET driven electronic loads, however, the former are not capable of operating under a wide variety of voltage and current ranges found with FET driven electronic loads. In addition, FET drive dynamic electronic loads are much more expensive than passive resistive load modules. Thus, there remains a need for a hybrid load system that has the versatility of a dynamic electronic load with the cost-effectiveness of a passive resistive load.